@thyname Thanks once again. What I found out was that Innuos's Squeezelite version only supports up to DSD 64. I can clearly hear the difference between 64 and 128. Anyway, I'm now using Zenith as the 'regular' Roon core, and it works like a charm. Thanks for your assistance.
By the way, I tried to swap back and forth between sonicTrasporter i5 and Zenith as Roon cores, and honestly I can't tell any difference. They both sound fantastic. Also, maybe I'm in the minority here but I actually prefer Roon 1.8 (SQ-wise) to Sense 2.0. It is a bit fuller and I kinda like it. Sense is probably more neutral/accurate, and I can see how someone else might prefer it over Roon. Both are excellent, it's really a matter of preference at this point.
Now I'm trying to figure out how to 'merge' (not replace) music from sonicTransporter's Roon core to Zenith such that it does not replace what I already have in Zenith, but simply add on top of what already exists.
I posted my query on Roon forums ...